Our project contributes to understanding the full range of meanings of cohabitation. We will ultimately use our indepth interviews to assist in questionnaire development for a larger-scale, representative data collection effort. In the 1970s family researchers largely ignored unmarried cohabitation, but now cohabitation is recognized as an important feature of family formation and children's well-being. Nearly all our knowledge about cohabitation is based on nationally representative or census data. We need to move beyond these data sources to better understand the meaning and implications of cohabitation. Qualitative methods allow us to develop a potentially richer and broader understand of the meaning of cohabitation. We can better evaluate the implications of the growth in cohabitation for adults and children once we gain an improved understanding of the meaning of cohabitation We expand upon our current understanding of cohabitation by conducting in-depth interviews with young white, Black and Hispanic men and women who are cohabiting or have had cohabitation experience. We focus on three important aspects of cohabitation. First, using symbolic interactionist perspectives on exchange, we investigate the rewards and costs, commitment levels, types of investments, interactions, and degree of attachment experienced by cohabitors. Theoretically, we argue that two key features of cohabitation -its impermanence and lack of institutionalization - structure these relationship qualities. Second, we examine the considerations underlying transitions into and out of cohabiting unions, including partners' views of marriage at the start of cohabitation and the bases for decisions to separate or to marry. Third, we evaluate perceptions of the acceptability of parenting within cohabitation and adults' obligations to children born and/or raised within cohabitation. We focus on race and ethnic differences and similarities in the meaning of cohabitation. Superficial treatment of race and ethnicity in the study of cohabitation is problematic because cohabitation is central to union formation and childbearing among minority men and women. Applying Gaines' (1997) theory of culture and interpersonal relationships, we argue that, through cultural and socioeconomic variation, race and ethnicity structure cohabitation's relational dimensions, transitions into and out of cohabitation, and perceptions of parenting by cohabitors.